Technical Field
The present invention relates to laser cladding apparatuses and their operating method.
Background Art
For instance, in order to form a ring-shaped valve-seat of a cylinder head for internal-combustion engine, metal powder is supplied to a valve-seat portion (portion to be processed) from a powder supplying device while applying laser there from a laser oscillator for cladding of the metal powder supplied. Such a processing method is generally called laser cladding. For a favorable cladding state by laser cladding, it is important to adjust the timing to start laser irradiation and to supply metal powder to the portion to be processed appropriately. If the timing to apply laser and supply metal powder at the time of start of cladding is not appropriate, unwelding or alloying with base material occurs, thus leading to a failure in cladding of a desired quality, and the product obtained may be faulty.
Patent Document 1 discloses one exemplary means to solve this, and the device for determination of start timing of metal powder supply described there includes: reach timing measurement means to measure timing when metal powder supplied from powder supply means reaches the cladding portion (portion to be processed) in the state where laser light to be irradiated for cladding by welding is not applied; and supply timing determination means to determine the starting timing to supply metal powder with reference to the irradiation of laser light during welding based on the measured reach timing. Specifically, an optical sensor is disposed at a portion to the processed, the optical sensor including a phototransmitter and a photoreceiver to detect the reach timing of powder, and the start timing to supply metal powder with reference to irradiation of laser light for welding is determined based on a signal from the optical sensor.